To Catch a Rat
by cls2256
Summary: When Azkaban suffers overcrowding, all the inmates are put two to a cell. Due to odd numbers between genders, Sirius Black is stuck with a female cellmate temporarily until a women's cell becomes available— much to his dissatisfaction. Over the month they spend together, Sirius finds that his timid, shy cellmate might just have been the best thing to happen to him.
1. Chapter 1

**Hi Everyone! Here is the start of my 4 part series: Sirius Black's Happy Ending! I will be updating a couple of times a week to catch up with the other sites I publish on, as I am currently writing installment 3 of the series. There's a lot of content to get moved over to , and I'm very excited to be bringing you all this story! The main pairing here is Sirius Black x OFC. The concept of Allie wormed its way into my heart, and I hope you all fall in love with her as I have.  
**

**To Catch a Rat follows a one-month timeline and takes place timewise during the summer between CoS and PoA.**

* * *

**DAY 1**

"76…77… 78…"

The cement floor was cold against his bare back as Sirius Black performed his daily fitness routine. He started off every day with sit-ups, push-ups, and jumping jacks— mostly because there wasn't much else to do.

Azkaban Prison had been his home-sweet-home for the last almost 12 years, each day the same mundane routine; wake up 6:30, breakfast at 7:00, shower at 8:00, lunch at 12:00, rec hour at 3:00, dinner at 6:00 and lights out at 10:00. Every day for over a decade, he lived by this schedule; the only activities to keep him occupied in his cell were his fitness regime and books that the prison house-elves would deliver to his cell twice a week. He was one of the prison's longest tenants, most of the others serving a life sentence allowed themselves to wither away in misery, dying only a year or two after their arrival.

Sirius wasn't like most of the other prisoners who were sentenced to life like himself, for he didn't belong there. He was innocent— framed for the crime he was found guilty of. This piece of the puzzle was the only thing that kept him going, kept him willing to wake up in the mornings, and eat his three square meals a day. He would watch the prisoners who served shorter sentences come and go, envious of their release back into the world. If only he would've been allowed a trial, if only they'd listen to him when he told the Auror's that it was actually his former friend— Peter Pettigrew— that blew apart a street full of muggles, rather than him on that fateful night. But alas, the only surviving witness wasn't sure what they saw, and the only thing left of Pettigrew was his finger.

Halloween Night 1981— The night he would never forget, the night that changed his life for the worse; the night that filth Pettigrew, someone he had called a friend, betrayed James and Lily Potter, leaving their son— his godson, an orphan.

How he wished he was on the outside, to see his godson, Harry. He would be 12— almost 13, and hopefully just as confident and handsome as James had been. It should've been him raising Harry, as James and Lily had wanted it, rather than the boy being sent off to his muggle aunt and uncles while he rots in prison.

"148…149…150"

Sirius wiped the sweat from his brow as he stood up, stretching before beginning his push-ups. He cracked his neck as he looked at the wrought iron bunk bed set in his cell, wondering if the rumors were true.

"I heard they stickin' us with roommates— prisons overcrowded, there ain't no more room!"

He had overheard another inmate, Rod Thorson, say this during rec hour a few days before, but there hadn't been any news or notice if this was indeed the case. In his nearly 12 years of incarceration, he never had to share his cell, something he was thankful for. The 9x9 cell had its own sink and toilet, but there was no privacy to it; if he had to take a shit, he would have to do it right in front of his cellmate. Even worse, the cellmate would have to take a shit right in front of him.

"22…23…24…"

"Black!" a voice called to him, accompanied by a bone-chilling cold that swept through his entire cell.

"25… 26… 27…"

"BLACK!"

Sirius stopped his push-ups, feeling the familiar flood of dread accompanied by dementors. He stood up, looking at Wilson— the prison's director and only human guard, and two dementors, standing just on the other side of the bars of the cell.

" What? " he said, his voice dripping with irritation.

Wilson was a tall, plump man with a bald head so reflective it looked like it had been shined with floor polish. Sirius looked at him contemptuously, running a hand through his shoulder-length unruly hair.

"You're getting a cellmate this afternoon, get this shithole cleaned up!" Wilson barked.

Wilson was referring to Sirius's unmade bed, which he usually left messy just to tick off him off when he came by barking orders. He was always unnecessarily crabby, for which Sirius chalked up to having dementors follow him around all day.

"Fuck," he whispered under his breath. "Yes sir," he added sarcastically.

"And put a goddamn shirt on, for merlin's sake!" Wilson called back as he and the dementors skirted away down the hall.

Guess the rumors were right; he was getting himself a roomie. He huffed as he fixed his bed to look somewhat presentable and then got back down on the floor to resume his workout. He was irked, not looking forward to having to eat, sleep and shit in front of another stranger that was probably going to be a total whack job, or worse— a former Death Eater.

"28…29…30…"

"Black!"

Sirius looked up from his book, giving guard Wilson an apathetic look. He felt the familiar chill down to his bones as a lone dementor floated ominously behind him. Sirius was lying down on his bunk, ankles crossed, dressed in the thin cotton striped uniforms that all inmates of Azkaban wore.

"Your cellmate is here— Murphy has to bunk with you for the next month until I can transfer her to the other side" Wilson grumbled as he unlocked the cell, sliding the iron-barred door open.

"Her?" Sirius asked incredulously, sitting up quickly.

A tall, pale young woman with wild curly hair stepped inside the cell, clutching a pillow and folded blanket and looking frightened out of her mind. She wouldn't meet Sirius's eyes and trembled like a small dog.

"Wilson— she's a lady, what the hell?" he growled, his eyes darting back and forth between the guard and his new cellmate.

"Prison is overcrowded, and there are odd numbers— she's gotta stay somewhere for the next month until a women's cell opens up," Wilson said with a shrug. "Home sweet home, sweetheart" he added to the girl, slamming the cell door back shut.

Sirius got out of bed and pressed his face against the cell bars "I can't share a cell with a lady, where's the goddamn decency?"

Wilson was already halfway down the hall before Sirius had even reached the cell door. Warmth returned to the air as the dementor following him floated further away. Sirius sighed heavily and swore under his breath before turning back to the girl standing in the middle of his cell— their cell.

"Murphy, was it?" He said stiffly

"y-yes," the girl replied softly, "Allie Murphy."

"Sirius Black," he said flatly, bowing grandiosely to her "Pleasure to make your acquaintance." His tone was dripping in sarcasm, "Your bunks up here."

He pointed to the top bunk as he plopped down on his bottom bunk mattress heavily. Allie didn't move, clutching her bed linens to her chest tightly.

"I remember hearing about you; you're the Death Eater that killed all those muggles…" She said, her voice soft, timid.

"That's me, the Dark Lord loving murderer serving a life sentence for blowing apart a street of 12 people— and a filthy rat," Sirius said cynically, picking his book back up.

Allie took a step backward, shifting awkwardly on her feet, her eyes darting around the cell.

"What're you doing?" Sirius asked with a sneer as he grabbed his book, lying back down. "Get your bunk set up."

Allie opened and closed her mouth a couple of times without speaking. Sirius looked at her, narrowing his eyes. She looked absolutely terrified, and she was staring at him as if he was going to pounce on her at any moment. He realized she was afraid of him, afraid to move too close.

"Sweetheart— I'm not going to hurt you..." He said, his tone much gentler.

She swallowed hard and then nodded before slowly making her way to the bunk ladder, crawling up to her bunk to set up her bed. They were silent as he listened to the sound of her sheets rustling, the sound of someone else making noise in the cell a very foreign concept.

"Uhm, I have to pee…?" Allie said her voice as quiet as a mouse.

"Toilets right there, help yourself," he grumbled.

He turned away from her, trying to give the poor girl some privacy to do her business. He shook his head and sighed, speaking under his breath.

"Where's the goddamn decency?"


	2. Chapter 2

**DAY 2**

Azkaban's recreation yard was a sad excuse for anything that remotely resembled a yard. Located on top of the prison, the ground was cement, and separating the inmates from the sky was a canopy of wrought-iron bars, caging them inside. A few tables were set up at the perimeters of the yard that the inmates would sit at to play cards or smoke cigarettes. It was always cold in the rec yard, even on a sunny day. Dementors floated above them on each side, just outside of the bars.

"Heard you got yourself a lady roommate" Sirius was leaning against the wrought-iron cage, eyes closed as he listened to the waves of the sea 4 stories below. He opened his eyes to see the rubicund face and bloodshot eyes of Rod Thorson, grinning broadly

"She's a pretty thing— what's she in for?" Thorson said as he clasped a hand on Sirius's shoulder.

"Get your filthy hand off me— I've told you a thousand times, no touching" Sirius growled, shaking him away. "I don't know what she's in for, she doesn't talk."

"She's been in that cell with ya for a whole day! You didn't think to ask her what landed her in this shithole?" Thorson asked incredulously.

"Like I said— she doesn't talk."

Sirius looked across the rec yard at Allie, her bright red curls frizzing as she played with strands of her hair. She looked as if she were going to be sick, and he didn't blame her. It took time to adjust to the oppressive cold that the dementors brought. He wondered what she had done to land herself here— she was young and pretty, too shy to seem like she could've killed somebody.

"Well, I jus' can't believe they stuck ya with a lady— how long ya got with the little ginger?"

Thorson laughed wheezily, showcasing his yellowed teeth.

"A month" Sirius grumbled. "Then she'll be moved to the women's block."

"My roomie is that fat one, right over there—" Thorson pointed to a short, very plump man with a balding spot on the crown of his head. "Total whackjob—4 years for tamperin' with potions at St. Mungo's— used to be a Healer."

"Sounds like a nutter," Sirius said, only half paying attention to Thorson's ramblings as his focus was on watching Allie.

She sat with her knees to her chest, resting her chin on her knees as she seemingly waited for rec hour to be over. The other inmates kept looking at her over their shoulders, watching her curiously. Sirius studied her face, searching his brain for all possible situations that someone this young and good-looking could be here.

"So whatcha think— ya in, Black?"

"Hmm?" Sirius hummed, his attention snapping back to Thorson.

"Poker— get your head out of the clouds! Ya in?" Thorson jeered.

Sirius turned his attention to a couple of other inmates sitting in a circle on the ground, one shuffling a deck of cards.

"Oh, yeah, sure I'm in," he said.

He situated himself amongst the circle, Thorson continuing to ramble idle things as the inmate shuffling began dealing the cards. He looked over his shoulder at Allie, still in her seated spot in the far corner of the yard, twisting a strand of hair around her finger.

"Look alive, Black!"

He felt Thorson clasp a hand on his shoulder; Sirius swatted it away, sneering irritably.

"Touch me again, Thorson and I'll cut your hand off."

**DAY 3**

A quiet cell was something Sirius was used to, but with another person breathing the same air, the silence was deafening. Allie had barely spoken three sentences to him since arriving three days ago, so he followed suit and kept to himself. He waited until she was taken for her shower time to do most of his toilet business, as he found it utterly indecent to shit in front of a lady. She was given a separate shower time, which allowed him a whole 30 minutes in his cell alone. Sirius had a bet with himself to see just how long she could go without talking, for which she broke his own expectation twice over already.

He sat on his bunk reading as she splashed her face with water at the sink, she eyeing him in the mirror cautiously. He tried not to stare at her, as he knew he made her uncomfortable— his reputation preceded him. He wished Thorson shared just a slight bit of fear, as he was always up Sirius's ass in the rec yard and putting his hand on his shoulder. No matter how many times Sirius threatened to cut his hand off for touching him, Thorson still felt the need to give him a brotherly pat on the back.

"Why did you do it?"

Allie's soft and hushed voice startling Sirius— it was the first sound she'd made all day.

"So she speaks," Sirius said with amusement "Why did I do what?"

"Kill those muggles," she said even softer, leaning against the wall and fidgeting with the hem of her shirt.

Sirius took note of how beautiful the curve of her hips was. He was sure that underneath the thin fabric of the Azkaban prison uniforms, she had a nice figure. He let out a soft chuckle, smirking at her.

"I didn't kill them," He said, watching her brow furrow slightly, "I was framed."

"But there were witnesses, weren't there?" She asked

"Magic worked to my disadvantage that night," He said, "The man who really killed all those muggles turned out to be more clever than most of us thought."

Allie chewed her bottom lip as she locked eyes with Sirius for a few moments. After an awkward pause, she broke the stare and nodded.

"I believe you," she whispered, looking out the iron bar covered window of the cell.

"And why do you believe me?" Sirius asked cynically "because no one else does."

She shrugged, resuming fidgeting at the hem of her shirt. "You don't bear his mark," she said simply.

Sirius puzzled for a moment before he realized she was talking about the Dark Mark. He looked to his forearms; his sleeves were rolled up to his elbows, displaying his unmarked flesh. He chuckled softly, shaking his head.

"I would die before I ever sided with him."

Allie smiled slightly, looking out the window again and admiring the sunset over the North Sea. Sirius eyed her up and down, she didn't look quite so afraid anymore. The twilight sun made what bit of her hair touched by sunlight look almost golden, her curls still bouncy and full despite the harsh prison shower water. Her youthful skin was still so smooth and unblemished, unlike his. His' was beginning to show the stress of the dementor's effects after so many years.

"How old are you, kitten?" He asked, raising an eyebrow.

"23,"

Her voice was sweet but so soft Sirius could barely hear her.

"And how did you end up in here?" he asked, leaning forward, "what could you have done to land yourself in prison?"

She smiled a sad smile. "I stole."

Allie made her way to her bunk, not elaborating any further. Sirius questioned if he should press her for more detail, his curiosity starting to get the best of him, but chose not to. This was the most he had heard her speak in three days, and it continued to be, as she remained silent for the remainder of the evening.

**DAY 5**

Sirius was thankful for the 30 minutes he got alone while Allie was showering. Privacy was the one thing he was concerned about when he heard the rumor of cell sharing, and part of him felt like he was lucky that he got paired with a lady— solely for the 30 uninterrupted minutes that he could use the toilet or jerk off in peace. Thorson was complaining at rec hour how he couldn't 'play tug-o-war' because he had no free moment away from his psychotic, potion-poisoning cellmate. As much as Sirius never wanted to hear about or indulge Thorson talking about his masturbation time, he felt the need to brag that Allie had separate shower time, giving him a half-hour of undisturbed solitude.

Sirius had his nose in a book (his only form of entertainment), having finished his business 5 minutes before when he felt the familiar icy dread roll through his cell. A clank of the cell door sliding open got his attention as Allie stepped back into the cell, her curls damp and hanging limp, her arms wrapped around herself as she shivered. Wilson and his pet dementor had escorted her back from the showers, the cell door slamming shut with a loud clatter. Even after Wilson and the cloaked figure made their way down the hall, the warmth returning to the air, Allie continued to shiver as she made her way up to her bunk. She looked as if she were going to cry and be sick at the same time, her skin white as a sheet.

"You alright?" Sirius asked, as her shivering was shaking the entire bed frame.

"I'm so cold," she squeaked through chattering teeth "they make me feel like I'll never be cheerful again."

"You'll get used to the cold that comes with them, it comes and goes," He said, speaking to the bottom of her mattress "How long you got in here?"

"6 months," she replied softly.

"It'll be over before you know it," he said, trying to muster up a positive tone.

She didn't speak. Sirius stared at the bottom of her mattress above him for a few minutes, listening to the sound of the bedframe shaking from her constant shivers.

"What did you steal?" he asked, breaking the silence.

"Money"

She didn't indulge in the conversation anymore, so he didn't push his luck any further, turning his attention back to his book. He struggled to read, for he felt terrible for the freezing girl above him, and the sound of the shaking bunk made it hard to concentrate.

**DAY 7**

The sound of sobs cut through the silence, jolting Sirius awake. He rubbed his eyes, irritation flooding through him, as he was always grumpy when he was woken suddenly. Back in his Hogwarts days, James had thrown a Fanged Frisbee at him while he was sleeping once, waking him abruptly, and showing James and his other friends that waking Sirius Black out of deep sleep wasn't pleasant. For 12 years, he had gotten used to sleeping in total silence, his body used to waking up at the 6:30 alarm bell, and only waking up for that.

"Could you keep your blubbering down?!" he snapped, his voice low and gravelly from hours of not speaking.

"I'm— s-sorry" she squeaked; her sobs then muffled by her shoving her face into her pillow.

He exhaled as he rubbed his eyes, feeling a little guilty for snapping at her. He climbed out of his bunk and made his way up the ladder. He sat on the edge of her mattress, down by her feet with his legs dangling off the side.

"I didn't mean to snap at you." He said, his voice much calmer now, "what's wrong?"

He felt stupid when he asked this question.

She's in prison, you git. That's what's wrong

She sniffled for a moment, sitting up and leaning her back against the cement wall that their bunk set was pushed up against "I'm thinking of my family."

"Thinking about how much you miss them?" he asked.

He was met by a moment of silence, but her expression told him she was about to elaborate.

"I have 5 younger siblings, I worry about them getting fed," she said just above a whisper.

"I'm sure your parents are taking care of them," Sirius said

"My dad left when I was 16. My mum doesn't make much." Allie replied plainly.

"What does your mum do?"

"Cleans rooms at the Leaky Cauldron— she stayed home until Dad left, can't get a job doing much else."

Sirius thought about how to proceed carefully before speaking.

"Did you steal the money to help your mum?"

She nodded as she wiped her face "I dropped out of Hogwarts after 5th year to help her; I worked at a bakery, but it wasn't enough. I took the money from the till as we were closing up."

"And they caught you," Sirius said, a statement not a question.

"We had eaten only beans for the last month. I bought real groceries with money."

Sirius felt a pang of sadness for her— despite being disowned, he had never known such poverty that would've driven him to steal from his job to feed his family.

"What about you're other siblings? Any of them able to help your mum?" he offered gently.

"My one brother is 21 and left when he graduated, we haven't seen him since— just like dad. My one sister is 17; she's a squib who can't seem to hold a job. I also have a 12-year-old brother, and twin sisters who are 9."

"Their finances weren't great even before my dad left; I worry Mum can't handle it without me." She said through a sniffle.

"Is there anything I can say or do to make you feel better?" he asked, feeling thick as he said it. What was he going to do for her while they were stuck in prison, guarded by one fat bloke and a hundred soul-sucking demons?

"No, thank you," she whispered.

He nodded, "do you want me to go back down to my bunk, or do you want me to sit here with you?"

"You can stay if you like," she shrugged, fidgeting with her shirt hem.

"Alright,"

He adjusted himself backward, leaning his back against the cement wall with his legs outstretched in front of him. They sat in silence, comfortably; the only sound echoing in the cell was Allie's intermittent sniffles.


	3. Chapter 3

**DAY 13**

It seemed stupid to look forward to rec hour on Saturdays, but kickball was the highlight of Sirius's week. Only allowed on Saturdays, the men could usually get three games in during the hour spent in the cement yard. Sirius was the captain of his team, and one of the best kick-ballers in the men's cell block— thanks to 12 years of practice. He found it strange when he first arrived at Azkaban— a bunch of wizards playing a muggle yard game— but seeing as how none of them were allowed a wand, they couldn't play Gobstones or any of the usual wizard games. Their teams were the same each week— Rod Thorson was captain of the opposing team, and insisted on shaking Sirius's hand after each game, despite Sirius reminding him to 'keep his filthy hands to himself.'

Thorson reminded him of Peter Pettigrew; a sneaky brown noser with a hidden agenda, ready to kiss Sirius's boots until the opportunity to screw him over for personal gain.

Sirius was a tad more competitive with kickball this Saturday than he had been in a while; he found himself striving to hit his personal best kicks, diving further to catch the ball in the outfield, and running faster than typical between bases. He was on fire, his team chanting "Black! Black! Black!" every time he was up to kick. Allie watched from the sidelines, watching quietly as he dominated the game. He didn't want to admit to himself that he was showing off for her, wanting her to be impressed with his athletic ability, but he couldn't help but sneak glances over at her any chance he got. He admired the way the sunlight made her ginger curls almost sparkle, brightening his mood despite the dementors sucking all the positivity from the air.

She had seemed to warm up a little more to him, still quiet and shy, but much more relaxed and willing to make idle small talk since he sat with her in silence for nearly two hours as she cried over her family. He liked to hear her talk— she had a sweet voice, albeit soft, but it was soothing to his ears. She even made a joke that morning when Sirius told her about Saturday kickball.

" She has a sense of humor! " He had said, caught by surprise that she had cracked a joke.

Her fit of giggles was the cutest thing he had ever heard, but he forced himself to shake off any thought even remotely like that. She was his cellmate, they were in prison, and just because she had a cute laugh (or a potentially beautiful physique hidden under prison robes) didn't mean he should dwell on it.

He smiled at her again as he lapped the bases, feeling impressive as his teammates chanted "Black! Black! Black!" scoring another home run for his team. He felt his stomach flip flop when he noticed she was smiling back.

**DAY 15**

"Why aren't they leaving? It's so cold" Allie said through chattering teeth, shaking Sirius awake.

A few dementors had been circling their cell block; their close proximity sucked all the warmth out of the air. Sirius blinked at her a few times as he was waking up, noticing it was indeed much colder than it usually was at night.

"I don't know; sometimes they linger in one spot overnight," he said sleepily.

"I'm freezing, I've never been this cold before," she said softly, sitting at the edge of his bunk.

She was shivering hard, even wrapped in her blanket Sirius could tell that she was still having trouble adjusting to the frigid chill the dementors brought.

"You will get used to it," he said as he sat up.

"How long did it take you to adjust?" she asked

He chuckled "probably 6 months" he muttered with a sheepish smile.

"Great," she muttered, wrapping herself tighter. "Can I ask you something?"

"Sure," he said, furrowing his brow in curiosity as he sat up straighter.

"What happened that night?" she asked, her voice whisper quiet. "When you were framed…"

Sirius inhaled deeply, studying her face intently before speaking. Her eyes were a very light shade of green— he would've mistaken them for blue at first glance, but looking closely, they were indeed green.

"I had 3 friends— James, Peter, and Remus. They were the greatest friends, James especially. He took me in when my family disowned me." Sirius began. "James was married to Lily, and they had a son, Harry."

"Wait— James and Lily Potter? Harry Potter?" Allie asked; her typically soft voice almost at an average speaking level in her surprise.

"Yes— their location was protected by the Fidelius charm, and I was supposed to be the secret keeper…"

"So you were the one who sold them out?" she interjected.

"NO," Sirius said, a little too firmly as it made Allie jump and shrink away from him. "I would've died before I betrayed them. I was supposed to be the secret keeper, but we made a last-minute change."

Allie relaxed slightly, nodding at him to continue.

"We had a spy in the Order— The Order of the Phoenix was the resistance if you remember hearing that during the war— we had thought the spy was Remus but turns out it was Peter. I had convinced James to use Peter as the secret keeper instead— I as good as killed the Potters."

Sirius began to get a little emotional, recanting that horrible night that haunted him. He continued to tell her about how he had confronted Peter when they found out they had been betrayed, and how he blasted apart the street, screaming at how Sirius was the one who betrayed the Potters, as no one knew about the last-minute switch in secret keepers besides the Potters, Peter and himself.

"Thanks for telling me," she whispered, giving him a sympathetic smile.

He nodded, taking a deep breath to steady his emotions. He noticed she was still shivering, the icy chill still present around them. He wished he had a wand; he would cast a Patronus and drive those vile creatures away to keep her warm.

"You can sleep here tonight; it'll be warmer with both of us," he said, patting his mattress.

The moment the sentence left his lips, he instantly felt stupid. Did he really just offer a place in his bed to his cellmate? His _prison_ cellmate? To his surprise, she nodded and crawled up next to him. She spread her blanket overtop of his, and situated herself under both of them. Sirius laid back down, awkwardly sticking his arm out for Allie to curl up next to him, feeling his ears grow hot in embarrassment. His stomach did flip flops as she laid her head on his chest, wrapping one of her arms over his torso. He felt clumsy as he adjusted the blanket to cover her shoulders; he never used to be nervous around women in the past, why was he feeling this way now? Was it because it had been 12 years since he had even touched a woman? He felt her relax against him, her shivering starting to subside. He closed his eyes; this was a nice feeling— to be touched by another human being. He always got irritated when any of the other inmates even so much as brushed his shoulder, but here, cradling Allie as she drifted off to sleep, a tear slipped unexpectedly down his cheek. He didn't realize how much he had missed another person's gentle touch until this moment.

**DAY 16**

Throughout the next day, Allie seemed much more relaxed, almost even cheerful as they went about their day. Sirius took note in the few jokes she had made throughout the day, as well as spent rec hour walking laps, rather than sitting in the corner twirling a lock of her hair. They continued conversations throughout most of the day while they were in their cell, talking about their interests, lives, memories from when they were younger. Sirius had learned that Allie had been in Hufflepuff while at Hogwarts, obtaining seven O. before having to drop out to help take care of her siblings. She expressed her love for potions, her initial life's dream to be Healer at St. Mungo's, and to brew new potions to help the terminally sick.

"Taught by Snivellus, eh?" he had teased "I'm surprised you liked potions with him teaching."

"Professor Snape, you mean?" she had giggled "he was alright, nasty to some of the other students, but I didn't talk much so he left me alone."

"I was in school with Severus Snape— I hated that greasy haired prat."

"Maybe you didn't give him enough credit, he seems like he was quiet as a student, like me. Misunderstood."

Allie impressed him, the more she talked, the more he liked her. She seemed to be an uncommonly kind girl— just like Lily had been.

"At least its warmer tonight" Sirius said as they were crawling into their bunks.

"Yeah," she said softly, her voice as smooth as a soft breeze. "I slept better with you last night, though"

Sirius couldn't help but smile at this; he indeed had a great night's sleep with her curled up with him.

"You can sleep down here again if you wanted to," he said, trying to sound smooth and casual.

He felt awkward as he suggested it, mentally kicking himself for not having the same suave demeanor that he did before he was locked up. He used to be such the ladies' man, able to charm any witch he set his eye on. Now, he felt like he was stumbling in the dark like an inexperienced 14-year-old boy. To his surprise, Allie came slinking down the bunk ladder, crawling into bed next to him with a shy smile on her face. He allowed her to curl up against him like she had done the previous night, her arm snaking around his torso again. He smiled and closed his eyes, but his eyes flew open when he felt her lips press against his cheek gently. She kissed him softly, and when he looked at her, her face had flushed a deep shade of scarlet as she gave him a shy smile. His instincts took over, and he leaned in, pressing his lips against hers.

Fireworks! The kiss was electrifying. He had forgotten what it felt like to kiss. Her lips were pillow soft against his, and their tongues swirled together rhythmically. They kissed for a few minutes before his hand hesitantly slid up her shirt, moving slowly in case she would stop him. She didn't.

He cupped her breast, surprised to find it larger than he expected, it barely fit in his hand as he massaged her smooth flesh, running his thumb around her nipple. He could tell she liked it, for her soft moans against his mouth made the bulge in his pants grow larger by the second. His hand traveled down between her legs, his hand brushing against a patch of silky soft hair before slipping a couple of fingers inside. She gasped— music to his ears as he began to work his fingers inside her, kissing her neck as he relished in the experience of pleasuring a woman. It had been too long— too long since a woman had gasped and moaned for him. He felt like his old self— Sirius Black pre- Azkaban— watching Allie's facial expressions as he began to work faster, curling his fingers inside her. A wide smile crept across his face as he felt her muscles contract around him.

"Oh, oh, oh!" she cried, as a look of pleasure mixed with surprise splashed across her face as she came apart for him.

Sirius chuckled, watching her breathe heavily as her face puzzled.

"Why do you look so surprised?" he laughed, pulling her close to him.

"It was better than I expected" she giggled softly

"Thought I didn't know what I was doing?"

"No, no," she said quickly "I've just never…" she trailed off, her cheeks twinging pink.

"You've never… what?" he asked playfully.

She now flushed scarlet, not meeting his eyes and smiling sheepishly.

"You're trying to tell me you've never had an orgasm? Come off it— I know there are some terrible lovers out there, but certainly, at least you've rubbed one out before?" he asked incredulously.

"No…," she whispered, shaking her head and flushing even deeper.

"What? Well, you should start— especially if the boys you've been shagging can't get you off" he laughed.

He didn't think she could blush any deeper. She didn't respond to him, but by her demeanor, he started to put two and two together. His heartbeat quickened as guilt flooded through him.

"Oh— oh, you've never done this , at all, before…" he said slowly, a statement not a question.

She shook her head, chewing her bottom lip as she looked into his eyes. Sirius realized she had tried to tell him he had given her, at 23, her very first orgasm— in prison, his mind added. Had he taken advantage of her? He didn't mean to, she seemed very much to want it.

"Shit— oh, shit— Allie, I'm sorry, I didn't realize…" he stammered

"No, Sirius, it's ok," she said, her sweet voice relaxing him. "I wanted to" She smiled at him "I haven't had much time for dating since taking care of my siblings, and the only time I found myself in a broom closet with a bloke, Filch pulled us out before we could do anything."

Relief flooded through him as he saw her smile, her face only half-illuminated from the moonlight coming through the window.

"Damn Filch, such a buzzkill," he smirked. "You sure you're ok?"

"Yeah," she said, kissing his cheek. "I'm good."

They were silent for a moment, as Allie began chewing her bottom lip, eyeing him intently.

"What?" he asked, furrowing his brow.

"Can you do it again?" she asked softly, her cheeks flushing again.

Sirius smiled a wide toothy grin, chuckling softly as his hand trailed back down the front of her pants. "Yeah, kitten— I can do it again."


	4. Chapter 4

**DAY 17**

"135, 136, 137…"

"I can't believe you do those push-ups every morning," Allie giggled.

She watched from her bunk as Sirius performed his daily workout routine. He paused his push-ups, wiping the sweat from his brow as he smirked at her.

"I can't believe you are 23 years old and you've never masturbated."

Allie's cheeks flushed scarlet, looking away from him with a shy grin. "I was always too afraid to try…"

"Why? It's your body, how are you supposed to know what you like if you haven't tried it on yourself?"

Allie shrugged, chewing her bottom lip.

"Try it out, do it while I'm off at my shower block, or before you go to sleep," he suggested, resuming his final few push-ups.

"I don't know how," she said, flushing an even deeper shade of scarlet.

Sirius finished his push-ups, walking over to her and grinning. "Just start touching and see what feels good— and if you like something, keep doing it. There's no right or wrong way- it's fun, trust me."

"I trust you," she giggled softly.

"BLACK! MURPHY!" Wilson's barking voice called as he approached their cell with two breakfast trays, "eat up!"

Sirius grabbed both trays through the slot in their cell, handing Allie hers before plopping down on his bunk. He smiled as he ate his toast— as it turned out, getting stuck with a lady cellmate wasn't so bad after all.

The sunset was peeking in through the window as Allie and Sirius laid on their bunks respectively, Sirius's nose buried in a book. He had spent less time reading than usual since he had Allie to converse with through the day. She had been quiet up on her bunk for about an hour, Sirius assuming she was reading her weekly book as well. His attention to his reading was broken when he heard an audible exhale from the mattress above. He froze, his eyes now fixed on the bed above him as he listened to another soft whimper. He grinned, listening eagerly as she began to moan— sounding like she was doing an excellent job on herself up there.

"That's it, kitten— let it rip" he called to her, chuckling softly.

Her moans turned into gasps, and then silence fell. Sirius waited a moment before speaking, on the edge of his seat.

"How was that?" he asked eagerly.

"Fun," she giggled.

"I told you it would be"

**DAY 24**

"You know, you really are something when you get to talking."

Sirius outstretched his arm, allowing Allie to curl up next to him; they had begun sleeping together every night, staying up for a couple of hours chatting, huddled under blankets as he would try to keep her warm through the dementor's chill.

"I've just always been shy," she said sheepishly, nuzzling her head into his chest.

Allie traced circles gently on his chest as he breathed deeply. Sirius closed his eyes, almost drifting off to sleep when she caught his attention.

"Sirius?" she said softly.

His name sounded so sweet spoken from her lips— not only had no one really called him by his first name since he came to Azkaban, but there was something about the way she said it. Something about her voice made his name sound almost melodic.

"hmm?" he hummed, opening his eyes and looking to her.

She sat up, flushing as she began unbuttoning her shirt. Her breasts were a great slight, he instinctively reaching out to stroke one of them, feeling the goosebumps on her skin form as he touched her.

"Are you sure?" he whispered, sitting up to level with her.

"yes," she nodded, smiling shyly.

"Allie—" he said as his eyes trailed down to her slipping her pants off. "It might hurt a little"

"That's ok," she said softly, kissing him almost as soft as her voice was.

They snogged under the blankets for a few minutes before Sirius moved between her legs, ready to slide into her.

"If you want me to stop, just tell me, alright?"

"Alright," she smiled.

She was much tighter than any woman Sirius could remember— she cried out initially, Sirius clamping a hand over her mouth, so the other inmates didn't hear. He went slow, asking her in a whisper if she were alright periodically as they went round between his prison-issued sheets. She wrapped her arms around his neck as she moaned softly, allowing him to overtake her with pleasure. He had to fight to stay hard for her, 12 years of celibacy did not serve him well at this moment, but got extremely lucky that she climaxed just a couple thrusts before he did— his old rule of shagging was to never finish before the lady.

"Wow," she breathed, "that was fun."

"Did it hurt at all?" he said, kissing her forehead.

"Just at first" she smiled "only for a second"

He cradled her in his arms as they snuggled under the blankets, his heart feeling full of affection.

"Tell me something I don't know about you," She said sweetly, "something you haven't told me yet."

Sirius chuckled softly "well, I'm an Animagus— a dog" he whispered in her ear.

"Are you really?" she giggled "that's amazing— I'm jealous."

"Peter, James and I all were, we became Animagi to keep Remus company during the full moons— I told you he was a werewolf, right?"

"Yeah, you told me," she said softly, "I would love to be an Animagus, I'd want to be a bird, so I could get the best view of the world."

"It was some of the best times, the four of us running around the Forbidden Forest during the full moon."

His expression fell as he realized the best times of his life were with that filthy traitor Pettigrew— how he wished he would've known then that he would betray James and Lily.

Unexpectedly, Allie sat up slightly, looking at him intently. "Does the Ministry know you are an Animagus? Or the prison?"

"No, I'm unregistered… why?" he asked, his eyes narrowing.

"You could escape, go find Peter, and clear your name."

"What?" he asked incredulously, "Nobody escapes Azkaban."

"Dementors can't sense animal thoughts, you could get past them— if you are thin enough, you could slip through the bars."

"And then do what, swim across the North Sea to the mainland?" he asked cynically.

Allie shrugged, "I mean, yeah…"

Sirius looked at her intently; it actually made sense what she was saying. Since Wilson's fat ass wasn't there overnight, if he starved himself enough, he could slip through the bars and evade the dementors as the shaggy black dog. There was just one flaw in this excellent plan of hers.

He sighed heavily "Peter is dead, killed that night— the only thing they found of him was his finger."

"Well, It was just a thought," she said with a frown, laying her head back onto his chest. "If you do ever get out of here, you have to promise me something."

"What's that?"

"You have to come to find me when you're out. Even if it's just to say hello."

Sirius smiled, squeezing her gently. "I promise, if I ever make it out of this shithole, I will come to find you."


	5. Chapter 5

**DAY 28**

"You mean to tell me, Wilson, you have had male and female prisoners sharing cells?!"

"It's just Black and Murphy that have had to share; she's being moved in a couple of days once we release Dorinda Bartholdy."

"You don't put men and women in the same cell, Wilson! How thick can you be?!"

Cornelius Fudge's voice echoed through the entire cell block, shouting angrily as Wilson made excuses for the current cell arrangements.

"Murphy is in on a petty theft charge, whist Black is a murderer — he could've killed her with his bare hands— or worse, gotten her pregnant! "

Allie and Sirius heard the commotion and their names mentioned from down the hall of their cell. Allie wrapped her arms around him, burying her face into his chest.

"I think they're going to move me," she said, her soft voice almost inaudible as his chest muffled her. "I don't want to go."

"We knew this was going to happen here soon," He said soothingly "This arrangement was always temporary— it's going to be alright."

He held her tightly, listening intently to the arguing voices coming down the hall, getting closer to their cell.

"You should've put 3 to a cell before you put a woman with a man— oh, for merlin's sake, look at them!"

Fudge donned pinstripe robes and his signature lime-green bowler hat, looking too crisp and clean to be inside Azkaban prison. He now stood next to Wilson, glowering into Sirius and Allie's cell with a disgusted look on his face.

"They're— shit They're hugging!— goddammit Wilson I better not have to deal with any backlash from this!" Fudge snapped "Get her out of there, now! "

"Murphy, grab your stuff, let's go!" Wilson barked.

Allie pulled her blanket off the top bunk and folded it slowly. Sirius watched her as she took her time, moving at snail speed.

"Murphy, pick up the pace, let's go!"

"Remember what you promised me," Allie said softly, pulling her pillow down from her bunk.

"I will," Sirius replied, looking at her with a heavy heart.

He knew all along this moment was coming, but now that it was here, he didn't want to see her leave. Allie set her blanket and pillow on the bottom bunk, throwing her arms around Sirius and kissing him firmly.

"Oh for the love of…" Fudge muttered.

"MURPHY!" Wilson shouted angrily.

Sirius relished in this final kiss, taking note in the way her lips felt against his, the curves of her body molding into his. He snaked a hand into her wild mane of curls, wishing this moment to never end.

"MURPHY!"

Allie broke the kiss, a tear sliding down her cheek as she gave Sirius a sad smile. She grabbed her pillow and blanket and stepped towards the cell door.

"Don't forget me," she called, her sweet voice made Sirius's stomach flutter.

"Never!" he hollered back.

He watched as Allie was escorted out of sight by Wilson. Fudge lingered back, looking at him with revulsion.

"I better not have to do any incident paperwork that has either of your names on it…" He said, wagging a finger and shaking his head at Sirius. "Goddamn Wilson, putting the opposite sex together…"

Fudge turned on his heels to follow Allie and Wilson to her new cell when Sirius noticed the Daily Prophet sticking out of his robe pocket.

"Excuse me, Sir?" Sirius called to him, "Are you finished with your paper?"

"I am— what of it?" Fudge sneered.

"Do you think I could have it?"

He hadn't seen a newspaper in years and was curious as to how things looked on the outside.

"Why not" Fudge grumbled as he shoved the newspaper through the bars "have at it."

Sirius took the paper and lay on his bunk, feeling uncomfortable with how quiet his cell was. The redhead had really grown on him over the last 28 days; prison wasn't quite as lonely when she was here. He spent nearly an hour combing through the Daily Prophet, his eyes kept returning to a photograph of a large family in Egypt, waving and smiling back at him. Ministry of Magic Employee Scoops Grand Prize was written in large letters above the picture. He studied the family— The Weasley's, he knew of them— he had some Weasley cousins related by marriage, as the Blacks and the Weasley's were pureblood families. He looked at all the kids, studying their happy, smiling faces until he felt his stomach drop.

Situated on one of the boy's shoulders was a pet rat, its whiskers twitching and beady eyes blinking. Sirius heart his heartbeat in his ears, he knew this rat, this rat was unmistakable, for it was the rat that he spent every full moon with for years on the Hogwarts grounds. It was the rat that sold out his best friends— the rat, also known as Peter Pettigrew. Lo and behold, the rat photographed just so happened to be missing a toe on its front paw— curious, Sirius thought— the only remaining part of Peter that was found was his finger.

Sirius scanned the article, reading the text a few times over.

Arthur Weasley, Head of the Misuse of Muggle Artefacts Office at the Ministry of Magic, has won the annual Daily Prophet Grand Prize Galleon Draw.

A delighted Mr. Weasley told the Daily Prophet, 'We will be spending the gold on a summer holiday in Egypt, where our eldest son, Bill, works as a curse breaker for Gringotts Wizarding Bank.'

The Weasley family will be spending a month in Egypt, returning for the start of the new school year at Hogwarts, which five of the Weasley children currently attend.

Sirius stood and began to pace. The traitor was alive, living comfortably as a rat with a family that probably treated him as a beloved pet. It wasn't right— that filthy little scoundrel sold out James and Lily, killed all those muggles, and Sirius was rotting in prison for it. His anger rose, rereading the last sentence of the text again.

"Hogwarts" he whispered

Students were allowed a pet at Hogwarts, it would only make sense that the boy would take his beloved rat back to school with him come September the 1st.

"He's at Hogwarts!" Sirius hissed "HE'S AT HOGWARTS, HE'S AT HOGWARTS!"

Sirius began trashing his cell, anger flooding through him as he screamed over and over again. "HE'S AT HOGWARTS!"

"BLACK!" Wilson's short, clipped bark stopped him in his tracks. "Going nuts now that your girlfriend's gone?"

In his rage, he hadn't noticed the chill that came with Wilson's dementor until now, the cloaked figure floating ominously behind the fat guard.

"Is she alright?" Sirius asked,

"She's fine— here," Wilson held out a lunch tray "food."

Sirius reached his hand out to take it but hesitated.

If you were thin enough, you could slip through the bars. You could catch that rat and clear your name.

Allie was a goddamn genius, he was sure of it. What a curious coincidence that she would come up with that idea just a few days before he would learn that Peter Pettigrew was indeed alive— the one person who could corroborate his story and set him free. He waved the tray of food away hastily.

"Nah, I'm not hungry."

"Suit yourself" Wilson sneered, walking away, his boots echoing down the hall.

Warmth came back to the cell as the dementor floated away. Sirius began to pace in his cell again, stroking his chin as he thought.

He's going to be at Hogwarts, I know where he is going to be.

Sirius smiled, his plan of escape now flooding through his mind. He would starve himself thin, slip through the bars after Wilson left for the day and swim to shore. He could avoid being sighted, as he could live on the streets as a dog until he captured Peter and forced him to confess. Sirius looked out the small window of his cell, out at the rough waters of the North Sea, smiling as Allie's face came to mind. The shy little ginger that he was so angry he had to share a cell with ended up being a bigger blessing in more ways than one. He was going to get out of this shithole, and he would find her as he promised—maybe do something to help that family of hers.

But first, he was going to catch him a rat.

* * *

**Thank you so much for reading To Catch A Rat! This piece was short and sweet, but like all series it seems, each work gets longer and longer.**

**The start of the second installment in Sirius Black's Happy Ending, Be Careful What You Wish For, will be up in the next day or two, so make sure to add me to your favorite authors so you don't miss it!**


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